Detriot locker is the cheapest to get, but are getting more expensive. I believe that you can get one new for about $350 if you shop around, they were about $300 a year ago. It replaces the spider gears inside an open differential. If you have a carrier from a 14 bolt that originally came with a gov-loc then you will need to find a new carrier.
*edit* I forgot to mention that this is for a full floating 14 bolt only.
1973 K20 - 350/465/205
Edited by: 73K20 at: 2/18/04 8:56 am